I've kicked around the idea of getting another sub in my 21i now since winter when I redone everything. I've pulled a tape every way possible to get a box in the observer compartment. Then I built 2 separate boxes for the ski locker that didnt fit by about 1/2". This is the last thing I can think of, and the easiest. Im thinking about building an identical box, maybe not the same dimensions but same volume and same tune, as the box under the helm. I would have the interior guy pleat some white vinyl to match the center cushion already there, and cover the top of the box with it. I'd also cut 2 kick panels and have them pleated for both ends of the box. I'd start the sub box AfTER the center cushion that is already there. So the box and the cushion over the box would be offset from the center cushion about 6-8 inches. I dont really want the box 3'-5" long, which is the dimension from the center cushion thats already there, to the sub box baffle that is under the helm. Since they're both facing the cabin, would it phase or matter if the boxes are offset a foot from each other? I've got the 13w7 and 1000/1 v2 sitting around already. I also have carpet for a small amp rack under the observer compartment flip up seat back, which is the perfect size for that amp. I also already have the acrylic ring with LED's glued to it and stand offs. So I have stuff laying around to accomplish everything, besides a 100 bucks in wood. Since I cant get out on the water this weekend because of the cold weather, rain, and 20mph winds, I figured I might as well see if this is something I want to pursue. I know everyone is probably thinking just buy a new boat, but that's not going to happen this summer Anyone with their opinion or ideas on the phasing issue, or the look of it? I think if done like Im thinking about, it would look pretty badass, and sound even better!! I have 4 interstate 29's for a battery bank, rocker switches to shut amps off at party cove, and a perko switch to a starting battery, so Im not to worried about the draw on the house bank. Let me know what you guys think, Im wanting to start the box today. Ill attach my quick sketch and some pics.

Luckily I measured from the floor before I started building the box. The walkthru walls slope in at the bottom, throwing all my measurements off So now, there's not enough room for my port to be right next to the sub. The easy plan B would to have the port going horizontal, eathier on top or below the sub. Surely that wouldnt hurt anything as far as phasing would it? Waiting for the go ahead so I can get started.

Making a little progress if anyone cares
I got the sub box built. It's identical to the one under the helm, just with the port on top. I had to move the sub box back about 8"s so the seats would still open. So therefore I had to build a whole new bow cushion. It had a 10" offset from the lower bow cushion to the top of the box. Someone talked me into sloping a backrest on it instead of just squaring everything off. I need to test fit everything one more time, then the panels will b going to the upholstery shop.

Thanks. Neither sub has LEDs around it tho. Just speakers, amps, and cup holders. I didn't feel like making rings for the subs, and the w7s mount thru the rubber. The tower will b next for LEDs if I ever get around to it.

Not to thrilled with the upholstery guy. I even brought him a piece of the vinyl to copy off of to get the pleats and stitching to match up. The thread is white instead of silver like the rest of the boats pleats, and the diamonds are different size. :BangHead: Owell I guess. The sub is ready to mount. What do u guys think of it?

Thanks guys. Hopefully I will have finished pics of the install tomorrow. I still need to mount the box and trim panels, and mount the sub. Most of the wires to the new amp are already ran. I cant wait to hear both subs pound.

Got everything hooked up tonight and it slams! I have a distortion detector on its way so I can final tune everything. Ill take a video of everything when I tune it and its out of the unit. All you can hear is the tin trying to fall down